I have factory exhaust and i'm gonna remove my muffler to make it breath easier instead of doing the whole system to 5". Thers alot of dodge people around that have removed there mufflers and man are they loud. Does the duramax compare or is it quieter being a 8 cylinder ? While i have it at the muffler shop should i ask if they well make the downpipe 5" , looks like a tricky pipe to remove and make . I really want the turbo whistle so if the mufflers off and the factory 3.5" system still on this well increase right ?

Happy New Year all you Diesel Burners ... ;)

I Removed my stock muffler and put on a performance flow through muffler and a 4" pipe out the back. (stock before the muffler) And it has a lot more power and the turbo spools a lot more freely. Infact i can hear it at a idlol. BIG differance. cody

I removed mine and love the sound.
Ben

You can always change it if you don't like it. My Dmax was straight piped almost all of the time I owned it.... 72,000 miles

Do some research before going to the 5" pipe it may be too big of a pipe.

When I was looking for an exhaust there were some web pages that recommended only going 5" if you modified your motor with a chip and bigger air intake. It appears if the pipe is too big there is not enough pressure to flow the gasses out efficiently.

One site actually had calculations that showed a decrease in HP when using a 5" over a 4" on a stock motor. They sold both systems so I don't think they had any hidden agenda behind there recommendations.

Also remove the cone out of the turbo, I assume the d-max's turbo has on but I havent got to looking yet. Doing that made the turbo on the cummins i had a lot louder

"cone out of the turbo" ?
is there one ? i read alot of duramax forums and never heard of this. anyone else ?:confused:

No cone, that's a Cummins thing only

I thought there was only room for a 4" downpipe. Every 5" system I've seen use a 4" downpipe and then go to 5" from there.

Down pipes are very difficult to find for our trucks since there is little room to begin with, and the turbo outlet is oval shaped instead of round. Some may be calling the front pipe the down pipe. The down pipe is the one actually connected to the turbo. The front pipe starts where the down pipe ends, on the lower end of the firewall. A four inch system will flow enough air for most people. I think you need 600+ hp to see any difference.

I ran a straight pipe and took it off due to the noise in the cab around 65 MPH. A good muffler will not make a performance difference, only a sound difference. I am now running the dual MPRP system and like it very much. There is no performance gain from the dual system, only the ability to completely smoke out an intersection when the need arises. The dual system does have a slightly shorter muffler than the single. The sound is great! Louder on the outside and still quiet on the inside.

And the wife knows when you coming home you can hear that thing a mile away.

I removed my muffler on my 2001 Duramax and am truely impressed! Cab noise is a little louder at about 2000rpms. SOUNDS AWESOME!! I also dropped about 150 EGTs.

K&N,Edge Juice with attitude

Has anyone had a problems getting there trucks inspected after removing the muffler? I have mine removed and am due for an inspection.

I removed my muffler on my 2001 Duramax and am truely impressed! Cab noise is a little louder at about 2000rpms. SOUNDS AWESOME!! I also dropped about 150 EGTs.

K&N,Edge Juice with attitude
Does it have a good tone? I want a little more noise but don't want to sound like a Kenworth pulling 60,000lbs. Did you jusy cut the muffler off and weld in a new piece?

On a 4" bully dog exhaust you can install the muffler backwords.This gives you a straight thru shot and a muffler for inspection.Sounds kinda mellow not loud,but Im half deaf damn Detroit Diesels!